7.
Remove the
five
screws securing
the thrust
bearing cap and bearing assembly.
The ballscrew
assembly can
now be
withdrawn
from
the left
hand end
of the saddle.
Remove
the
bearings
from
the ballscrew.
8. To
replace a new
ballscrew, reverse the disassembly
procedure, paying particular
attention to
the
following:
a. The
ballscrew assembly
is supplied
from
the original manufacturer
protected in
lanolin, and
this must be completely
removed.
Wash the assembly
by completely immersing
in
CLEAN
white
spirit
(NOT
PARAFFIN) and brushing
well.
Run the
ballnut up the
full length of the
screw to
ensure
complete
removal. Allow the
screw to drain
for
an hour
and
blow
dry using
a
water-free
airline. Lighdy
oil
with
a mineral
based lubrication
oil
(Mobil
DTE 24
or
similar)
ensuring
all moving
parts
are lubricated.
Fit
a
plastic
ball
(BM
part number 8303822)
to
plug
the radial lubrication
hole not used
-
refer
to the
old
screw
for its correct
position.
b.
When
refitting the axis thrust bearings
ensure
that the
bearings
are back-to-back,
on Fafnir
bearings, this is
with
the
stamped
faces
of the outer rings together.
To
ensure best results the
high points of eccentriciry should
be together
so ensure
the round burnish
mark
on each
bearing
is axially in
line.
If
there
is any doubt about the condition
of these bearings they
should be
replaced.
c.
The alignment
of
the ballscrew with
the bedface and master
guideway is critical and must
be
within
0.050
(0.002")
along the
full
length
of the ballscrew.
When
the
screw
alignment
requirement
has been set tighten the
bearing cap
screws
to
9
Nm
(80
lbin). Recheck the
alignment
of
the ballscrew.
d.
Wind
the ballnut to
the
right hand end of the saddle
prior to refitting the table.
Ensure the
ballnut
is
positioned
with
the lubrication hole uppermost, ready
to refit the lubrication
pipe
e.
Always
refit
the saddle
end
covers as
soon
as is
practical and never run the
machine under
power
without
the
saddle
end
covers
in position.
9.
Adjust the X axis belt tension as per
Section
7.7.1.
10.
Reset
the
software limits as
per
Section 7.6.3
11.
Set the
X
axis gib
strip
and
keep
plate
and check lost motion as per
Section
7.9.1
12.
Reset the
X axis
backlash
compensation as
per
Section
7.9.2
7.4.2 Y
Axis Ballscrew Assembly Removal
To
ensure
that no damage
occurs to the Y
axis ballscrew during this procedure, two people are
required, one
to
withdraw
the
knee
front
bracket
and
maintain
the
alignment
of the assembly,
whilst the
second
person
removes
the pulley
and
guides
the
ballscrew from the
knee.
WARNING: DISCONNECT POWER
TO THE MACHINE
BY THROWING THE
MA]N
CIRCUIT'
BREAKER
TO THE'OFF'
POSITION.
1. Remove
the two neoprene
covers on the top of
the knee.
2.
Remove the
drive belt housing
cover and handwind
the
saddle
forward.
3.
Remove the
stop
pin
on the knee front
bracket
and slide covers forward
7-to
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